[Devel] [PATCH RHEL7 COMMIT] fuse kio: Introduce fast path protocol version,

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-693.21.1.vz7.50.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-693.21.1.vz7.50.3
------>
commit 21edce574b4ec285a4f57e4c8f194f053df67ced
Author: Kirill Tkhai <ktkhai at virtuozzo.com>
Date:   Wed May 30 14:48:58 2018 +0300

    fuse kio: Introduce fast path protocol version,
    
    Send fast path version on PCS_IOC_INIT_KDIRECT request
    and check the userspace answered version is the same.
    Note, that patch changes PCS_IOC_INIT_KDIRECT ioctl()
    cmd number, since struct pcs_ioc_init_kdirect becomes
    bigger.
    
    https://pmc.acronis.com/browse/VSTOR-10131
    
    Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
    Reviewed-by: Pavel Butsykin <pbutsykin at virtuozzo.com>
---
 fs/fuse/kio/pcs/pcs_fuse_kdirect.c | 15 ++++++++++++++-
 fs/fuse/kio/pcs/pcs_ioctl.h        |  3 +++
 fs/fuse/kio/pcs/pcs_prot_types.h   |  5 +++++
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/fs/fuse/kio/pcs/pcs_fuse_kdirect.c b/fs/fuse/kio/pcs/pcs_fuse_kdirect.c
index 930ddff1b680..a4064904f963 100644
--- a/fs/fuse/kio/pcs/pcs_fuse_kdirect.c
+++ b/fs/fuse/kio/pcs/pcs_fuse_kdirect.c
@@ -48,6 +48,16 @@ static void process_pcs_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 		fc->conn_error = 1;
 		goto out;
 	}
+
+	if (info->version.major != PCS_FAST_PATH_VERSION.major ||
+	    info->version.minor != PCS_FAST_PATH_VERSION.minor) {
+		pr_err("kio_pcs: version missmatch: must be %u.%u\n",
+			PCS_FAST_PATH_VERSION.major,
+			PCS_FAST_PATH_VERSION.minor);
+		fc->conn_error = 1;
+		goto out;
+	}
+
 	pfc = kvmalloc(sizeof(*pfc), GFP_KERNEL);
 	if (!pfc) {
 		fc->conn_error = 1;
@@ -100,11 +110,14 @@ int kpcs_conn_init(struct fuse_conn *fc)
 	inarg = &req->misc.ioctl.in;
 	outarg = &req->misc.ioctl.out;
 	inarg->cmd = PCS_IOC_INIT_KDIRECT;
+	info->version = PCS_FAST_PATH_VERSION;
 
 	req->in.h.opcode = FUSE_IOCTL;
-	req->in.numargs = 1;
+	req->in.numargs = 2;
 	req->in.args[0].size = sizeof(*inarg);
 	req->in.args[0].value = inarg;
+	req->in.args[1].size = sizeof(*info);
+	req->in.args[1].value = info;
 	req->out.numargs = 2;
 	req->out.args[0].size = sizeof(*outarg);
 	req->out.args[0].value = outarg;
diff --git a/fs/fuse/kio/pcs/pcs_ioctl.h b/fs/fuse/kio/pcs/pcs_ioctl.h
index 6451baabb492..14d4fc33fdf1 100644
--- a/fs/fuse/kio/pcs/pcs_ioctl.h
+++ b/fs/fuse/kio/pcs/pcs_ioctl.h
@@ -10,6 +10,8 @@
 #include "pcs_map.h"
 #include "pcs_rpc.h"
 
+#define PCS_FAST_PATH_VERSION ((PCS_FAST_PATH_VERSION_T){1, 0})
+
 #define PCS_FUSE_INO_SPECIAL_ ((unsigned long long)-0x1000)
 
 struct pcs_client_lease_info
@@ -35,6 +37,7 @@ struct pcs_ioc_init_kdirect
 {
 	PCS_NODE_ID_T node_id;
 	PCS_CLUSTER_ID_T cluster_id;
+	PCS_FAST_PATH_VERSION_T version;
 };
 
 struct pcs_ioc_fileinfo
diff --git a/fs/fuse/kio/pcs/pcs_prot_types.h b/fs/fuse/kio/pcs/pcs_prot_types.h
index d8852f6ffda5..39a1d674cc96 100644
--- a/fs/fuse/kio/pcs/pcs_prot_types.h
+++ b/fs/fuse/kio/pcs/pcs_prot_types.h
@@ -73,6 +73,11 @@ typedef u64 PCS_CHUNK_UID_T;
 typedef u64 PCS_LEASE_GEN_T;
 typedef u32 PCS_POLICY_GEN_T;
 
+typedef struct {
+	u32 major;
+	u32 minor;
+} PCS_FAST_PATH_VERSION_T;
+
 /*
  * File attributes
  */